High-energy-density, ultralong-life manganese oxide composite carbon aqueous zinc-ion asymmetric supercapacitors

Transition metal oxide composites integrate the characteristics of metal oxides and carbon materials, thereby combine the advantages of both battery-type and capacitive electrodes. Using bimetallic aluminum‑manganese metal-organic frameworks (MOFs) as precursors, the MOFs are calcined under a nitrogen atmosphere, followed by etching in a sodium hydroxide solution to obtain the MnO/C (MO/C) composite material. The resulting high specific surface area composite material (583.76 m2 g−1) exhibits outstanding electrochemical performance, achieving a high energy density of 146 Wh kg−1 and a power density of approximately 1000 W kg−1 at a current density of 1 A g−1, along with excellent stability. Even under a high current density of 10 A g−1 and after 5000 cycles, the material maintains a capacitance retention rate of 96.7 %. The high specific surface area and abundant pore structures provide more electrochemical active sites, facilitating ion diffusion. The carbon framework enhances conductivity, effectively mitigating structural collapse caused by volume expansion during repetitive charge and discharge processes, thereby improving material stability. This study provides robust support for the development of high-performance electrochemical energy storage materials.